1. Field of the Invention
The present invention relates to a running control device for an industrial vehicle such as a forklift or the like.
2. Description of the Related Art
Industrial vehicles such as forklifts, wheel loaders, bulldozers and the like generally comprise accelerator means such as an accelerator pedal, accelerator lever or the like used to control the engine revolutions, a clutch pedal used to operate the forward clutch and reverse clutch of a transmission that transmits the rotational torque of the engine to the drive shaft, and a brake pedal and brake lever which are used to operate brakes that apply braking to the vehicle. Conventionally, in industrial vehicles with such construction, cases where so-called starting on a slope is performed, or in cases where the vehicle is started into motion in a state in which the vehicle wheels are riding over a step part as shown in FIG. 8, it is necessary to perform the simultaneous operation of the brake lever, clutch pedal and accelerator means. Specifically, the following operation is performed: namely, the accelerator pedal is depressed a little at a time while the brake lever is pulled, and the depressed clutch pedal is gradually released so that the engine driving torque is transmitted to the driving wheels a little at a time while the clutch is engaged; then, when a driving torque that is equal to or greater than a specified value has been transmitted, the break lever is completely released, and the vehicle is started into motion while the engine revolutions are increased by means of the accelerator pedal.
However, the following problems occur in the abovementioned prior art.
In the case of industrial vehicles such as forklifts and the like, it is often necessary to perform load transporting work on sloping road surfaces or step parts on road surfaces. In such cases, unless the vehicle is started into motion at a very low speed or stopped at a very low speed, there is a danger of collapse or spilling of the load or the like. In order to prevent slipping in the opposite direction in the case of uphill starting on a sloping road surface or step part on the road surface as described above, three operations, i.e., the operation of the accelerator pedal, brake lever and clutch pedal, must be performed simultaneously. Accordingly, operation is extremely difficult, so that the problem of a deterioration in driving operability arises. Furthermore, such an operation of starting the vehicle into motion at a very low speed or stopping the vehicle in place at a very low speed (so that there is no collapse or spilling of the load) requires a considerable amount of experience. Accordingly, there is a strong demand to make it possible to perform the abovementioned operation easily, without any need for experience.